A Mach-Zehnder Modulator (MZM) interferometer is an extensively used type of interferometer. Interferometers are widely used in research and industrial applications to measure small displacements, refractive index changes and surface irregularities. An interferometer uses the interference of light waves to make precise measurements. The interferometer uses superposition to combine waves in a way that provides a meaningful property that may be diagnostic of the original state of the waves. For example, if two waves of the same frequency combine, their resulting intensity pattern is determined by the phase difference between the two waves. Accordingly, in-phase waves will undergo constructive interference and out of phase waves will undergo destructive interference when the waves are combined.
Typically, an interferometer will separate two waves and each wave will take a different path. A path difference, due to the different distances traveled by each wave, creates a phase difference between the waves. One of the paths may be used for diagnostic measurements. The waves are then recombined before arriving at a detector. Interferometers have many application, including in physics, astronomy, telecommunications, biology, medicine and seismology.
A MZM interferometer is more versatile than some other interferometers, including Michelson interferometers. In an MZM interferometer the light paths are well-separated and each light path is traversed only once. MZM interferometers have many applications, including in aerodynamics, quantum mechanics, plasma physics, heat transfer and telecommunications. In optical telecommunications, an MZM interferometer may be used as an electro-optic modulator for phase modulation of light as well as amplitude modulation of light.